CLEMSON, S.C. — The Clemson Tigers need to replace two of their most productive offensive players from last year: receiver DeAndre Hopkins and tailback Andre Ellington.

Coach Dabo Swinney and the Tigers opened spring practice Wednesday without their record-setting receiver in Hopkins or their two-time, 1,000-yard rusher in Ellington. Hopkins gave up his senior season to jump to the NFL while Ellington exhausted his eligibility last fall.

Both were big reasons why Clemson set records on offense and went 21-6 the previous two seasons. The Tigers won their first Atlantic Coast Conference title in two decades in 2011 and followed that up with an 11-win season — their most victories since the 12-0, national championship season of 1981.

“That’s just football, everybody’s got holes to fill,” Swinney said. “I think we’ve got good guys here and good guys coming in to help us fill those holes.”

They are some fairly major holes.

Hopkins had 82 catches for a school record 1,405 yards and an ACC record of 18 touchdowns. His sliding catch for a first down on fourth-and-forever in the final minute of the Chick-Fil-A Bowl kept the Tigers game-winning drive alive on the way to a 25-24 victory over LSU last New Year’s Eve.

Ellington ran for 1,082 yards and eight touchdowns, becoming just the third tailback in school history with two seasons surpassing 1,000 yards. Ellington was on the sidelines watching his former teammates go through drills in preparation for 2013.

At receiver, the Tigers again seem loaded even without Hopkins. The group is led by Sammy Watkins, a freshman All-American in 2011 who could not match his production because of suspension and injuries this past season. Swinney said Watkins has been a leader in the offseason and is confident he can return to form this fall.

Behind Hopkins are regular contributors in Adam Humphries, Charone Peake and Martavis Bryant, who Swinney says is working to come back from his academic suspension before the bowl game.

Humphries and Peake combined for 66 catches while four of Bryant’s 10 catches went for touchdowns.

The ground game

Running back is a less secure situation.

More than two-thirds of the carries in Clemson’s high-speed offense came from Ellington and returning quarterback Tajh Boyd. Last year’s backups of D.J. Howard, Rod McDowell and Zac Brooks were used mostly as fill ins with Howard, with 83 rushes in 13 games, getting the call most often. None of them have shown the breakout speed of Ellington while he was primary backup to ACC player of the year C.J. Spiller in 2009. That hasn’t damped Swinney’s hopes his backs can step up this spring and fall.

“Replacing Andre Ellington is certainly a challenge because this guy’s one of the all-time leading rushers at the school,” Swinney said. “But I think everybody that watched us play last year can agree that Rod McDowell showed a lot of great promise.”

Among the returnees is ACC player of the year in quarterback Boyd, who passed on the pros to play a final season at Clemson. Boyd passed for 3,896 yards and 36 touchdowns, both school single-season bests.

He acknowledged he second-guessed himself about his future for a week or so after announcing his intentions to return. Once that passed, Boyd said he threw himself into offseason workouts with the intention of leaving an even bigger mark on Clemson than he has the past two seasons.

Not even seeing New York Jets coach Rex Ryan on the sidelines at practice — Clemson holds its pro day Thursday — made him regret his choice to come back. Boyd says it’ll be different without Hopkins and Ellington but has confidence in Clemson’s returning skill players.

“Those guys who some people have been waiting for to step up, they’re excited about the challenge this presents,” Boyd said. “And they’re ready to be known as well.”